A calorie is a calorie: weight theory made easy

Some of the money-making myths and legends of the diets and exercise industries have been punctured by a piece of common-sense research from the US. It's simple conclusion? A calorie is a calorie is a calorie.

'It's all about the calories,' Dr. Eric Ravussin of Louisiana State University told Reuters. Eating less and exercising more are equally good at helping take off the pounds.

The study, published in the Journal of Clinical Endocrinology & Metabolism, is one of the few done under controlled conditions that can actually demonstrate what happens to a human body while dieting and exercising. It challenges many of the popular tenets of the multibillion dollar diet and fitness industry. It found, for example, that there is no way to selectively lose belly fat or trim thighs and added to the evidence that adding muscle mass does not somehow boost metabolism and help dieters take off even more weight.

'So long as the energy deficit is the same, body weight, fat weight, and abdominal fat will all decrease in the same way,' says Ravussin.

Ravussin's team were testing volunteers for another reason -- to see if taking in fewer calories helps people live longer. (Strict diets have been shown to help animals from worms to dogs live longer, but it takes longer to study monkeys and humans.)

• They tested 24 people, 12 who ate a calorie-restricted diet, and 12 who dieted and also exercised five times a week for six months.
• The dieters ate 25% less than normal, while the exercisers reduced their calorie intake by 12.5% and increased their physical activity to lose an extra 12.5% in calories.
• Another 10 volunteers acted as controls. All food was provided by the university in carefully measured portions for most of the study.
• The volunteers in both groups lost about 10% of their body weight, 24% of their fat mass, and 27% of their abdominal visceral fat. Visceral fat is packed in between the internal organs and is considered the most dangerous type of fat, linked with heart disease and diabetes.

The distribution of the fat on the body was not altered by either approach helping prove that there is no such thing as 'spot reducing', Ravussin said. It suggests, he added, that 'individuals are genetically programmed for fat storage in a particular pattern and that this programming cannot easily be overcome.'

Ravussin has published other studies that also dispute the idea that exercise builds muscle that helps people lose weight. 'If anything, highly trained people are highly efficient, so they burn fewer calories at rest,' Ravussin said.

Dieting alone also did not appear to cause the volunteers to lose muscle mass along with fat,. 'There is a concept that if you exercise, you are going to lose less of your muscle,' Ravussin said. But his team found no evidence this is true.

Don't misunderstand this research. Ravussin still stresses that exercise is crucial to health. 'For overall health, an appropriate program of diet and exercise is still the best,' he said.

As to the original purpose of the research, his team found some small suggestion that cutting 25% of calories by either diet or diet and exercise might extend life.